9.8 4 st tohatsu

[hipster dufus]

took my new 9.8 out this past weekend.i mixed some 87 octane with some older,3 months, 89 octane. had a hard time getting the motor to idle. it started right up but would die. it was more of an annoyance then a problem. put all the old gas in my truck. that is the only thing i have done different.does the gas make that much difference? could it be something else? the throttle linkage seems to have some slack in it, i might just being a bit too anal. but i will run only new 89 octane from now on ouy with stabil.will i have a hard time taking iy into a service center under warranty?i bought it online. thanks

 

[TOHATSU GURU]

Re: 9.8 4 st tohatsu

If your problem is fuel related it isn't covered under warranty as it is something you caused. Every dealer is required to offer warranty service regardless of where purchased so anything that is under warranty wouldn't be an issue.

 

[sschefer]

Re: 9.8 4 st tohatsu

The new Tohatsu 4 strokes run better on 87 octane than they do on 89. Tohatsu Guru will back me up on that. My Nissan 18 ran at idle all day long on 87 but would miss and burp on 89. Stay off the Ethanol stuff if you can also. Chevron with Techron is the best for all the 4 strokes.

 

[pvanv]

Re: 9.8 4 st tohatsu

The 9.8 has a loop in the throttle rod to allow the choke to increase idle while choking, without binding against the throttle cables. So a loose rod is normal -- and is designed that way. If the cables are really loose, that's a different issue. They should have almost no slack. Not tight like a guitar string, but ever so slight slack on the "push" cable side when at the throttle stop.

The 9.8 should idle like a swiss watch. All of mine do. Yes, minor changes in fuel quality (not so much octane, but age, formulation, water and contaminants) will affect idle, especially if the idle stop screw is set a little low. You may want to check the in-gear warm idle with a shop tach to be sure it's right.

As always, try to avoid ethanol if you can. E-10 will run OK if fresh and clean, but if the boat can accept one, I would definitely install a water-separating filter (looks like an oil filter). That way, any minor phase-separated water will get the chance to drop out before it gets to the carb. Once you have even a few water droplets in the carb, they will NOT burn through, and must be drained. If so, you will need an 8mm wrench to remove the drain plug from the carb. Running a good fuel additive designed for E-10 stabilization, such as K-100 MG (at all times), while no substitute for good gas, is cheap insurance.

 

[hipster dufus]

Re: 9.8 4 st tohatsu

before i get all stupid and mess something up. where is the 8mm drain screw? is it below the carb, like on other 4 strokes.i will try that along with some new gas. thanks

 

[sschefer]

Re: 9.8 4 st tohatsu

The easiest way to keep from doing something stupid is to go get a shop manual. Locations for things can change even in the middle of a production run.

 

[TOHATSU GURU]

Re: 9.8 4 st tohatsu

It's the only horizontal bolt on the carb bowl.

 

[pvanv]

Re: 9.8 4 st tohatsu

As ss noted, documentation always helps. For an exploded diagram, you can d/l a free copy of the parts catalog from tg's website at http://www.internetoutboards.com/PartsCatalogMenu.htm. Any dealer can get a service manual for you. The language translation of the 9.8 service manual is not perfect, so reading it takes a little patience.

TG is correct as usual. The drain is on the starboard side of the lower corner of the carb bowl, and is the only horizontal screw there.

 

[hipster dufus]

Re: 9.8 4 st tohatsu

i own a shop manual. i can see the drain bolt on every other small engine i ever worked on. iam really just being careful. i appreciate the help.i will see what i can do thanks

 

[hipster dufus]

Re: 9.8 4 st tohatsu

looking at the carb, 8mm hex head with a slot on lower left corner of carb. will proceed to drain and run a better grade of gas. thank u all for ur assistance

 

[gary - k7gld]

Re: 9.8 4 st tohatsu

The only non-ethanol gas available locally, is the 91 octane premium - runs and idles perfectly on my new Nissan 9.8 at about 4000 ft elevation here in eastern Oregon...

 

[hipster dufus]

Re: 9.8 4 st tohatsu

well drained my carb today, ran new chevron 87 octane with starbrite enzyme treatment and marin stabil. took a few tries but i got it to idle smoothly after a few minutes.my question is , does the gas really make that much difference?i have no idea who has non ethanol fuel,i figured the treatments would take care of this problem. does it really run better on 87 octane? thanks

 

[TOHATSU GURU]

Re: 9.8 4 st tohatsu

The octane isn't important as long as it is at least 85. What is critical is that it be fresh and clean. It's much better to use left over fuel in your car rather than saving it for your next boating trip 30 days later.

 

[hipster dufus]

Re: 9.8 4 st tohatsu

1/2 turn in on the idle adjust seems to have solved my problems. will idle now for extended periods w/o shutting down.the choke will kick in every once in a while and surge is that the way it is suppose to run?thanks to everyone for their help. iam a dufus after all.

 

[pvanv]

Re: 9.8 4 st tohatsu

The choke should not close unless you engage it during startup. If this is an electric choke, you may have a wiring issue.